In late 2014, Adobe released version 4.0.1 of ADE [Adobe Digital Editions] in response to the privacy critiques.
That new version of ADE now uses HTTPS, rather than plain HTTP, to encrypt transmissions to Adobe’s log collecting server. The JSON payload with the reading progress information is also itself now encrypted.
To summarize: ADE is at least no longer transmitting reading information in the clear for anybody to intercept, but they are still collecting some for DRM ebooks.
Here are some links with more details:
Problems with the version of ADE you’re using?
When certain errors happen with your installation of Adobe Digital Editions, I find it helpful to first try an earlier version of the software.
My current go-to is Version 2.0.1, available from Adobe at: http://www.adobe.com/support/digitaleditions/downloads.html