PUP.Optional.Wajam is the detection name for Wajam, a browser add-on marketed as a “social search.”
PUP.Optional.Crossrider is a Potentially Unwanted Program (PUP), specifically a type of adware. It offers a highly configurable method for its clients to monetize their software. The common method to infect the end-users is software bundlers. The installers usually resort to browser hijacking. Targeted browsers are Internet Explorer, Firefox, Chrome, and sometimes Opera. Crossrider not only targets Windows machines but Macs as well.
PUP.Optional.Crossrider installs are typically triggered by bundlers that offer software you might be interested in and combine them with adware or other monetizing methods.