File format: The “type” of file, indicated by the file extension (the letters after the file name). For example, a Word document has the .doc format, while an image can be .jpg or .bmp.
Goal Rate: The number of actions (or goals) completed, divided by the number of clicks received. For example: you might set up a “signing up for our newsletter” goal on the home page of your website. If 10 people click from your ad to the homepage and 2 people out of those 10 sign up for the newsletter, your CR is 20%.
Hashtag: A way of indicating the subject of a Twitter post, prefixed with the # symbol. Hashtags are essentially the meta-data of Twitter. They also help people search for content and track social media activity.
Index: A database created by search engine robots which contains information on the [glossary]URL[/glossary] of each page crawled, the keyphrases it contains together with other information which determines weighting in SERPs such as keyword density, formatting and PageRank.