Return Emails or bouncing emails.

Is anyone else having trouble with emails?  During the recent blog hop, I had several people tell me their emails had bounced coming to me.  This week someone else said the same thing.  I don't know what's going on. I don't know if it's Intenet Explorer, Yahoo or Blogspot, any ideas?  I'm sorry if I don't get your email, please try again. I do like getting mail from everyone so please know that it's not me!