CBD by itself doesn't get you high, but some recreational users pay attention to it because it modifies the THC high, damping down THC's tendencies toward tension, anxiety and paranoia.
In the opinion of many, THC with some CBD provides a more calm, centered, relaxed high.
It's why cancer patients who've had prescription Marinol (single-ingredient synthetic THC capsules) often prefer natural cannabis, finding it less jittery and anxiety-making.
It's responsible for many - but not all - of the medical effects of cannabis. It's a very effective anti-inflammatory and has anxiolytic and antiemetic effects, plus it's a useful antioxidant and neuro-protectant that readily crosses the blood/brain barrier. (THC provides most of the painkiller effect, and most of the appetite enhancement.)
CBD-only products - oral tinctures and topical salves - are legal over-the-counter even in non-MMJ states. Just search Amazon for "Cannabidiol"
As a medication, it's fabulous, IME.
Personally, I use Dixie Botanicals' "Hemp Oil Salvation Balm" as a topical anti-inflammatory for sore or pulled muscles. I have Morton's Neuroma, and first began using it to calm the burning neuralgic pain that I get from being on my feet for prolonged periods. Then I tried it on sore muscles.
I also use "CB-DOOs," a mostly-CBD candy from my MMJ dispensary, about the same way other people use aspirin or naproxen or ibuprofen (which I can't use due to the gastric-bleeding side-effects of NSAIDs). Nice systemic oral anti-inflammatory, even in small (3-4 mg) doses, IME.
CBD is also being investigated clinically for use against cancer, and seems, in high concentration and topical applications, to show promise against some very aggressive breast and skin cancers.
It's a pretty impressive drug.