What are these blue and yellow cables coming out of my house for?
As best one can see from that resolution those are twisted pair cables.  The blue is probably a Cat5e or Cat6, for ethernet, and the yellow is probably Cat3/VG for phone.  If you look closely you should see the rating on the jacket.

If your area has or is scheduled to receive fiber-optic com utilities then some vendors (like FIOS) put the fiber terminal outside and split off the various services from there.

If they're not connected on either end they're safe to remove, but I'd leave terminals in case you want to connect service so you don't have to drill back through the siding.