Did you think Twitter was just for fun? That your tweets were just harmless irrelevant mutterings into the electronic ether?
You're wrong. You're taking part in a massive market-research study.
The news, which may surprise some, is that Twitter has found another way to monetise its service, having partnered with a firm which will make it simple for market researchers working for big companies to search and analyse the last two years of your Twitter updates.
Regular Twitter users can only search the site for messages posted in the last seven days or so, but Twitter has granted DataSift access to the full Twitter Firehose, allowing the UK-based firm to monitor and analyse tweets from the last 24 months, and even record sentiments and the location of Twitter users.
As the BBC reports today, DataSift is the first company in the world to offer their business customers access to potentially valuable information.
What's that? You thought that tweets you posted months ago had vanished like your breath on a cold day, or were simply hidden away so deeply and awkwardly on the Twitter website that they would be too difficult to uncover?
If you aren't comfortable with firms being able to mine your past tweets - and potentially gather information about you - you may wish to delete your old postings and think more carefully about what you share publicly on the internet in future.
Furthermore, if you haven't already done so, you may also wish to change your Twitter account settings to prevent the site from sharing your physical location when you post a tweet. Twitter offers the ability to delete location information from tweets you have made in the past.
Users who have set up "private" accounts on Twitter (rather than the more normal "public" accounts) are not included in the site's accessible archive of old tweets, and so can not be shared with market research firms.
Remember this - whether you use Twitter, LinkedIn, Facebook or indeed any other website - if you don't want it to become public, don't post it on the internet.Follow @NakedSecurity