There's an interesting post over at the Resurgence by Justin Anderson called 5 Critical Lessons From a Church Merger.  Anderson's points are (please read the whole post for his explanation):

1. You may not be leading your church as well as you think.
2. Patience actually is a virtue.
3. Don't underestimate your congregation's capacity for change and vision.
4. Together is better - and it's the future.
5. Relational connectivity is the key.

I really appreciate the reminder from point #3. 

Anderson's example is particularly interesting, however, because he went through a merger of three healthy churches.  Normally a church merger involves at least one church that needs a lot of help, but all three of these churches essentially gave up their independence to become campuses of the same church together (as I understand the facts). 

I praise God for the evident humility and passion for the gospel that must have brought this merger about.  And I think that this kind of thing is consistent with the multi-site logic.  But I have to admit that I don't relish the thought of there being fewer churches and more campuses out there in the world.  It'll be interesting to see if this becomes more of a trend.