I had an interesting conversation over the weekend regarding the Microsoft - Yahoo! bid which revolved around discussing the future direction of the web. One comment I made was that the ability for the search engines of the future were that 'targeted' advertising would not fulfil it's potential.
My reason for this is that people are becoming more aware of how their information can be used - as we saw when Facebook's 'Beacon' advertising backfired in November '07. Purchases on external sites were posted on Facebook profiles so people could share their purchase history. This freaked a few people out, and even made Mark Zuckerberg apologise on the facebook blog.
Well this is all well and good, and may appear to be a victory for the consumers - but it's not.. not at all. I'm sure the information is still kept 'behind the scenes.' It's for this reason that I'm slightly glad that Microsoft got in bed with Facebook ahead of Google. Imagine two years' worth of your home computers search results (the time Google claim they keep someone's search history on their servers) mixed with the demographic information available via analysing your own (and your friends') facebook profiles. That's a helluva lot of information to use to target someone. With or without publishing it.
Therefore, I'll come to the conclusion that on-line advertising is going to get much more powerful - and not just in how it's targeted (although that will have a fundamental effect). Since adverts can be targeted so well, the chances are that we'll see them slide into the background, rather than the traditional way of popping up several pop-ups to annoy the hell out of you. Your search results' adverts won't just be tailored via your keywords, but by your previous results, demographic, and a whole lot more.
I know that sometimes (in my vain moments) when I Google for myself, up pops some very old information. Given massive independence by my parents as a young teenager - I was allowed 1 hour a day on the internet. My name is attached to loads of old information - some of it looks as though it could have been published yesterday too.. luckily for me none of it is controversial.
This is one of the reasons that I can see the benefit of an OpenID-like system. Imagine giving someone control so that they stored their information? I sign up to facebook - my OpenID server gets sent the database schema - and I can control what bits are passed on to facebook. Other sites could then do alternative mappings, so that they could get my facebook data off my server - and have their own databases schematics too. It's not an idea that would work - as caching information is far to easy.. but the principle is nice.
So Control - we don't have much control over our information on the net. My advice - don't post anything controversial. Also, don't post anything interesting - or insightful - or material other people may read.. it may just come back and bite you in the bum.