Trying to search for old tweets can be a pain. Twitter's own search engine brings back limited results and the top search engines like Google and Bing are so focused on real-time that trying to get something older than a couple of days is almost impossible. Often times you will find yourself scrolling through your timeline looking for that one tweet you sent months ago. If you tweet a lot, that is a giant hassle.
PostPo.st thinks that it has come up with the solution. When you sign up for the service PostPost will determine 200 of your most relevant follows and index up to 400 tweets for each user. If some of the people you follow are also PostPost users then nearly all of their tweets will indexed. PostPo.st attempts to be as comprehensive a Twitter search engine that exists today.
PostPo.st will not only bring you back search terms with your keyword in the tweet but it will also partially index the Web pages of the link that was tweeted. The example that Brad Noble, founder and product designer or PostPo.st, uses is that of "tsunami."
"Tweets are often terse. Especially those with links in them," Noble said. "In order to account for that, we index not only the Tweets themselves, but also key parts of target pages. So, a search for "tsunami" can bring back Tweets that are about the 'tsunami' even though they don't have the word 'tsunami' in them. Here's an example."
PostPo.st stops the number of relevant followers at 200 because it is following Dunbar's Number, the theoretical limit of the number of people with whom any one person can maintain a significant social relationship. This does two things: A) attempts to bring you the most relevant search results and B) takes a significant load off of PostPo.st's servers. If PostPost did not truncate the number of relevant followers and tweets it indexes it would not provide the useful information that you are looking for and every search that you do the engine would be crawling everybody you follow and all their tweets. The end result would be a very poor search result.
The interface of PostPo.st is not unlike a historical version of social media aggregator Storify that just went to public beta this week. If a user has posted a picture with a tweet, PostPo.st will open that picture in the search timeline the same way that Storify does when manually curating feeds. A good example of this was adult magazine Penthouse, which signed up for the service April 27 and tweeted a picture tweet search history for adult star Nikki Benz (no nudity, mostly safe for work).
For those that do a lot of user research (like corporate community managers, for instance), the more powerful the search tool, the more useful it is. PostPo.st has the potential to be the de facto Twitter search tool. It also looks like it might have a business plan through the use of its API and plans for smartphone applications. PostPo.st could license its API to a mobile developer to be the search smarts for an application, bring relevant and rich media to Twitter search results on the go.