In general, information is good for democracy.  But there are at least two ways in which information can be bad.

• Too much information leads to overload.  People in today's world tend to get overwhelmed by information.  In politics, there are so many news outlets and blogs and other sources of opinion that it can be very hard to keep track of everything.  This excess of information can lead people to feel like they are hopelessly uninformed because they cannot keep up with it all.  This may make them less likely to even try to participate politically.
• The wrong kind of information leads to cynicism.  So much of what we hear about our government is negative.  With so many news outlets, there is competition to bring us more and more of the negative news that gets TV ratings and page views on the internet.  All this negative news can get us to be very turned off by politics and can make us not want to participate.

In these two ways, excessive information can make us less likely to participate in our government, which is not a good thing for a democracy.