The difference? Be sure to point out why tricking you into installing it isn't malicious, why it's not malicious that after that it changes your default search provider to send your searches to them (privacy much?), and why it's not malicious that it's abnormally hard to remove (a quick Google will demonstrate the normal 'remove toolbar' steps don't work, even Wikipedia has a note and several links on this: https://en.wikipedia.org/wiki/Ask.com ).

It tricks people to installing it, reports your search activity (maybe other data? I can't find details, not installing it myself), and takes major, unnecessary steps to make it hard to uninstall it. Sounds like malware to me.

It's a malicious software that hijacks the browser, displays unwanted ads and changes the search engine/start page.

Most common search suggestions for Cydoor (well known adware): http://i.imgur.com/iXqJdzU.png

Most common search suggestions for Ask Toolbar: http://i.imgur.com/HziYjkZ.png

Looks pretty similar to me.