Generally speaking, I will provide comments here for everyone to see. If you prefer personal comments on the design page, I will be glad to do that.
First, thank you for posting designs. I appreciate the hard work you all have done and look forward to seeing the new designs as they come in.
General comments: I like bold clean fonts versus stylish/flowing fonts. I am a fan of a clean and memorable type. The slogan is a nice to have, but not a requirement of the logo. If it works with the flow of the design, great, if not, I can get the slogan on the site in other ways. And so everyone knows... 'a lot' is two words, not one.
One more note: the .com isn't a requirement either - the logo could contain either "Learnthat" or "Learnthat.com." The current logo doesn't have the .com and I don't think missing the .com is a problem - your call!
#1: The first thing that came to mind was "Airtouch Cellular." Similar arch in the logo. I use an arch in my parent company (ThatNetwork.com) logo, so I don't want to do that here. The font is nice, a little thinner than I would normally use, but fits well with the design. I do like how the slogan fits in with the logo.
#2 & #3: I don't like the font - too script for me. I didn't get the "bubbles" until I read your comment - it looks like an ice cream cone to me. The slogan definitely doesn't work here, it's unreadable in this font at that size.
#4, #5, #6: The idea of a light bulb is good, but I didn't like these logos. Is there any difference between them? There didn't appear to be.