As for sources on the Internet, this article gives a nice overview of the scholarly opinion, which has gone back and forth on whether the year 1000 was really such a big deal. For one thing, dating systems were not yet consistent, so different communities would have placed the turn of the millennium at different times. Quoted there, Bernard McGinn, a leading scholar of medieval religion (my big mistake at UCSB was dropping out of his class), describes the general mood this way:

Exaggerated emphasis on the turn of the millennium, or indeed any specific date in the list of the many at some time identified with the end during the five centuries between 1000 and 1500, tends to minimize the pervasiveness of apocalypticism throughout these centuries. Medieval folk lived in a more or less constant state of apocalyptic expectation difficult to understand for most of us today.

That, in addition to the Britannica article on eschatology from that period, suggests that indeed there were people out there claiming this, that or another thing. But I don’t think a case can be made that the whole medieval world was united about one particular date, nor is that a claim I made. Yes, some people got worked up about it or dates around it, just as they get worked up about other dates.

Perhaps it was irresponsible of me to add to the hearsay that the year 1000 was particularly special. What I meant by it was to show that there is a pattern here, a consistency, an apocalyptic habit in the (especially) Christian (and post-Christian) consciousness that rears its head from time to time.