I just got this message when trying to add a feed "You have exceeded the number of items in 'My content'. Please delete an item before adding another one. " to the 'Add a gadget by URL' section.
Is it serious? Have I really reached the max number of feeds I can subscribe to?
I do have a lot admittedly. But this is a deal breaker, if it's true I will be forced to use Google Reader. Which would be a massive shame as I've been a proponent of my.live.com since it started despite the fact it has not had an update for years.
We do have a limit of 400 items in the My Content folder, which keeps a link to all feeds and gadget that have ever been added to your pages. Feeds that appear on more than one page will be duplicated in the My Content folder and will count against the 400 item limit. I would suggest accessing the My Content folder (click "Add Content, then the My Content on the navigation bar) and deleting any duplicate items. This will remove the duplicate feed/gadget from one of your pages.
After you do this, you should be able to subscribe to additional feeds on your page.