Why does this happen on twitter?

[annymsgrl]

why the words after the # some are hyperlinked and others aren't what does that mean

[Wings]

If you add a hashtag to your tweet and you have a public account, anyone who does a search for that hashtag may find your tweet. Although any keyword with a # in front could be considered a hashtag, there are many commonly used hashtags. Aside from not using hashtags for spam purposes, there are no formal rules for hashtag usage. A few simple best practices we recommend include only using hashtags on tweets relevant to the topic, and not over-tagging a single tweet.