Picture it like a magnet that attracts all messages categorized by that topical word or phrase.

Don’t hashtag spam

Many of the hashtags have “meeting times” where educators agree to “meet and tweet”–that is, send out messages on a topic at a certain time on a certain day. If you do participate at the agreed upon time, you’ll see the tweets stream in live and participate in said conversation (via twitter) in what is nearly real-time. But if you can’t make it, the great part about a hashtag is that it does the sorting for you. You can search for messages assigned to a given hashtag anytime–tomorrow, Sunday night, or during your planning period next week.