A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

Type to find tags:
An email previewing, analytics and spam filter testing service.
A bookmarklet and web service to allow clipping and organizing bits-and-pieces of the web.
A web based IRC client.
A reference to data that the reader can directly follow, or that is followed automatically.
For questions about #hashtags, popular on services such as Twitter, Instagram, and Facebook.
A resource site for free and premium interactive guides.
A location-based social network. Discontinued March, 2012.
A now defunct free social networking site similar in practice to Facebook Platform and MySpaceID.
An achievement-based social street cred builder for developers where they can communicate, share, brag and get found.
Gojee curates recipes from users and allows one to search recipes by ingredient
A tool to auto-complete words as you type. This feature is currently restricted to Blogger.com
a functionality of Google Maps to provide public transportation directions in selected countries.
For questions about the web interface of Google Spaces
a tool for managing resources for programmers it' very likely that a question about it will best suited in other sites in the SE network, like Stack Overflow as it s…
For questions specifically about working with the Google Classroom app.
Google Correlate (http://www.google.com/trends/correlate/) finds search patterns which correspond with real-world trends.