Use baseboard to conceal wires?
Yes it's definitely possible. If you have carpeting you often can just push the wire under the baseboard in the gap left for the flooring.

Otherwise the most common option is to remove the baseboards, and then cut out a strip of drywall at the bottom of the wall. You hide your wires in this channel, and then replace the baseboards.  Make sure that when nailing your baseboards back down that you don't hit any of the wires.

The above advice does not apply to line-voltage wiring but can be used for Telco wiring.