A lot of us have come to believe the Internet is forever – once  Google gets it’s hands on some piece of content about you – or once you tweet something – and search engines record it – it’s history – forever (even though the Internet as we know it is been around about 15 years – still).

But …. what if the Internet isn’t forever?  Take Twitter – did you know that any of your “hash tags” and even most of your tweets might not be saved past 1.5 weeks? I found out about the limitation of Twitter when researching why a client’s Twitter activity, mostly vanished.

Twitter does not “delete” information. All of the tweets, along with the hashtag, are still there.The problem is that you can no longer search for them.

The Twitter Search API methods, which http://search.twitter.com actually use, are limited. You can only pull the last 1,500 tweets for a given keyword, and you can only look back about 7 days. You can’t query something from 3 months ago. The “look back period” is actually defined in the API documentation as being dynamic around a target of 1.5 weeks. I’ve found that, in most cases, it’s between 8 and 10 days.

Twitter is, however, a database. All of the tweets are stored in a database. The reason for the API limits is performance. The entire service would have to be restructured if you wanted to be able to run more complex queries. It’s possible you could email them and have them do it for you, but if they let everyone query for whatever they wanted with an indefinite timeframe, the database would explode and cause a black hole in the center of San Francisco.

Social Networks also own all the data and personal information you put on them, and what if, at some point, a social network closes shop – does all your data go with it?

It’s a paradox that in some ways, our digital identity is immortal, and, at the same time, extremely fragile.