In SharePoint 2013 (I think), when I open the site content, I see a lot of icons, representing lists, libs and other stuff:
I guess each of this icon represents a different kind of 'list', 'library' or other 'stuff'. But what exactly do they represent? What are the differences between those 'things'? Why do you require so many different 'list-thingys'?
top left icon is a list similar to a table. It consists of columns and rows. each column is a field like "title", "description" or you can add your own custom field like integer, date/time, text or what ever you needs may be.
any type of list you create will have the image above.
the next one to the right is a document library specifically for image. Its base is a list but it stores images and each image can have information in a little list like title size and you can also add custom fields to that as well.
any type of image document library you create will have the image above.
from the top left go down one and you have another kind of document library, same as an image library but for documents like word, excel, pdf or any other.
any type of document library you create will have the image above.
the globe with a chain is a list for displaying links to other locations or websites.
any type of linked document library you create will have the image above.
the last one on the image is a task list. This refers to workflow items that have tasks assigned to them. On a normal list you can setup a workflow like an approval. When a workflow gets to the approval stage (a task for a user) its stored in workflow task. This usually contains the persons name that the task is assigned to, the date started, date edited, outcome and the linked item (from what list this task is associated to).
any type of task list you create will have the image above.
the last one above is a list that stores site pages like aspx pages that you can create.
they all have a list to store meta data and each one has slightly different functionality. If you were to build any custom library depending on what type of library you choose will determine the image that is displayed unless you change it obviously.
I think it takes some time to get familiar with these icons. They can be changed programmatically, but basically, the tabular one represents the Custom List App, Folder with a file in front should be Document Library template, With Media libraries having media in front of the folder. Link lists have link icons, Tasks lists have tasky-looking icon. Actually almost everything under that screenshot inherits from base type list, but they have different templates so they are represented by different icons.
I think if you go to apps you can add you'll see which icon belongs to which list type.
Every list serves unique purpose. The type of list that you use depends on the kind of information that you are sharing.
Announcements : Use an announcements list to share news and status and to provide reminders. Announcements support enhanced formatting with images, hyperlinks, and formatted text.
Contacts : Use a contacts list to store information about people or groups that you work with. If you are using an email or contact management program that is compatible with SharePoint technologies, you can view and update your contacts from your site in the other program. For example, you can update a list of all your organization's suppliers from an email program compatible with SharePoint technologies, such as Outlook. A contacts list doesn't actually manage the members of your site, but it can be used to store and share contacts for your organization, such as a list of external vendors.
Discussion boards : Use a discussion board to provide a central place to record and store team discussions that is similar to the format of newsgroups. If your administrator has enabled lists on your site to receive email messages, discussion boards can store email discussions from most common email programs. For example, you can create a discussion board for your organization's new product release.
Links : Use a links list as a central location for links to the Internet, your company's intranet, and other resources. For example, you might create a list of links to your customers' Web sites.
Promoted Links : Use this list to display a set of link actions in a visual layout.
Calendar : Use a calendar for all of your team's events or for specific situations, such as company holidays. A calendar provides visual views, similar to a desk or wall calendar, of your team events, including meetings, social events, and all-day events. You can also track team milestones, such as deadlines or product release dates that are not related to a specific time interval. If you are using an email or calendar program that is compatible with SharePoint technologies, you can view and update your calendar from your site while working in the other program. For example, you can compare and update your calendar on the site with dates from your Outlook calendar, by viewing both calendars side-by-side or overlaid with each other in Outlook. See Create a calendar for more info.
Tasks : Use a task list to track information about projects and other to-do events for your group. You can assign tasks to people, as well as track the status and percentage complete as the task moves toward completion. If you are using an email or task management program that is compatible with SharePoint technologies, you can view and update your tasks from your site in your other program. For example, you can create a task list for your organization's budget process and then view and update it in Outlook along with your other tasks. See Create a list for more info.
Project tasks : Use a project task list to store task information with a Gantt view and progress bars. You can track the status and percentage complete as the task moves toward completion. If you are using an email or task management program that is compatible with SharePoint technologies, you can view and update your project tasks from your site in your other program. For example, you can create a project task list on your site to identify and assign the work to create a training manual, and then you can track your organization's progress from Project. See Create a list for more info.
Issue tracking : Use an issue-tracking list to store information about specific issues, such as support issues, and track their progress. You can assign issues, categorize them, and relate issues to each other. For example, you can create an issue-tracking list to manage customer service problems and solutions. You can also comment on issues each time you edit them, creating a history of comments without altering the original description of the issue. For example, a customer service representative can record each step taken to resolve a problem and the results. You can also use an Issue Tracking list with a Three-state workflow to help your organization manage issue or project tracking. See Create a list for more info.
Survey : Use a survey to collect and compile feedback, such as an employee satisfaction survey or a quiz. You can design your questions and answers in several different ways and see an overview of your feedback. If you have a spreadsheet or database program installed that is compatible with SharePoint technologies, you can export your results to further analyze them. See Create a survey for more info.
Custom : Use a custom list to start a list from scratch. You can also create a custom list that is based on a spreadsheet, if you have a spreadsheet program that is compatible with SharePoint technologies. For example, you can import a list from Excel that you created to store and manage contracts with vendors. See Create a list based on a spreadsheet for more info.
External lists : Use an external list to work with data that is stored outside SharePoint, but that you can read and write within SharePoint. The data source for an external list is called an External content type. Unlike a native SharePoint list, an external list uses Business Connectivity Services to access data directly from an external system (such as SAP, Siebel, and Microsoft SQL Server), whether that system is a database, Web service, or line-of-business system.
Custom list in Datasheet :View Use Custom list in Datasheet View to create a blank list similar to a custom list but to display the list by default in datasheet view. Datasheet view provides a data grid for viewing and editing data as rows and columns. You can add and edit rows and columns, apply filters and sort orders, display calculated values and totals, and conveniently edit data in the grid cells. Datasheet view requires Office installed on a 32-bit client computer and a browser that supports ActiveX controls.
Status list : Use a status list to display and track the goals of your project. The list includes a set of colored icons to communicate the degree to which goals are met.
Circulations : Use the circulations list to send information, including confirmation stamps, to your team members.
Microsoft IME Dictionary list : Use the Microsoft IME Dictionary list to when you want to use data in the list as a Microsoft IME dictionary. You can convert the Reading column items to Display using Microsoft IME and view the content in Comment in the IME Comment window. The data can be linked to a specific URL.
PerformancePoint Content List : Use a PerformancePoint Content list to store dashboard items, such as scorecards, reports, filters, dashboard pages, and other dashboard items that you create by using PerformancePoint Dashboard Designer.
Languages and Translators : Use a Languages and Translators list with a Translation Management workflow in a Translation Management Library. The workflow uses the list to assign translation tasks to the translator specified in the list for each language. You can create this list manually, or you can choose to have this list automatically created when you add a Translation Management Workflow to a Translation Management library.
KPI List :Use a KPI list to track Key Performance Indicators which allow you to quickly evaluate the progress made against measurable goals. You can set up KPI lists to track performance by using one of four data sources: manually entered data, data in a SharePoint list, data in Excel workbooks, or data from Analysis Services — a component of Microsoft SQL Server. After the KPI list is created, you can use it to display the status of the indicator on a dashboard page.
Import Spreadsheet : Create a list that uses columns and data of an existing spreadsheet. Importing a spreadsheet requires Microsoft Excel or another compatible program.
refer MSDN for more details.
Gaurravs' answer explains what each type of list is for quite effectively.
Other answers here show the icons for 2013, which the question was for, but there's no similar reference for icons in 2010.
Since this is a top google result when searching for the same question in 2010, here's a screenshot demonstrating all the different icons and their names on the create screen.
Only exceptions (this was an existing site I added all these to so I could figure out what another site's lists were) are:
Now hopefully the next person who has this question in 2010 won't have to do likewise.
