If you are going to do this, you need to do it before March 1st. It has been said that users will not be able to do anything about this after that date.
With reference to Google's policy changes and how everything you do with your Google account will be tied together into their super-cauldron of information, you will probably want to clear your Google Web History out - if you turned that feature on - before month's end. After that, you won't be able to clear it, and everything you search for will be connected with your account.
To check settings and/or clear out your Web History:
1. Go to Google. If you aren't signed in already, do so.
2. In the top right-hand corner you'll find your email address or name, perhaps an icon if you have a Plus account, and a little downward facing arrow. Click on the arrow and a menu will pop up.
3. Click to 'Account Settings'. This will take you to a page called 'Accounts'. (If you have a Plus account, you might go via a Plus sign-in page.)
4. Scroll down to a section called 'Services'. Here you'll find an option called 'View, enable, or disable web history', which has a link next to it. Click on the link.
5. If you never turned web history on, you'll get a page asking if you want to turn this service on. Just click 'No Thanks' and all is good. If you did turn it on, you should have a list of your searches. At the top there is a button that says 'Remove All History'. Click this and follow the instructions which will remove all items from your Web History and pause the feature so nothing else will be added in future.
Also, you can completely remove Web History as a service from your account by clicking
THIS LINK, checking the tick-box and confirming you want to remove Web History. To be safe, it is probably best to do the steps above first to remove any history that might have already been collected.
Edit: I don't know if this will spread to the journals that have already posted (probably not) but with reference to the 'invalid' page upon clicking the link. I only just managed to replicate that and since I did not have the Web History service turned on for the account in question, I can only assume that you only get that page if there is no service to remove - most people who have reported it said they knew they didn't have the service turned on (this can easily be checked by going through the earlier steps to clear the history) - obviously you cannot remove something that isn't there, thus making the page redundant for that account.