.co is Colombia's country code TLD. But in 2010 the Colombian government opened it to international sales, and because "co" is short for "company" in English, .co became a .com alternative for business and startups. Notable examples: angel.co (AngelList — a startup investment platform), about.co.
.co advantages
"Co" — short for "company" — clearly business-oriented. Fits new startup or company brands.
As short and modern as .com. Users remember it quickly.
Availability — many well-known words are taken on .com but free on .co.
Premium feel — new and modern.
.co drawbacks
User error — visitors may type .com. That's a big loss for the .co owner (someone else may own the .com).
SEO and country-code — Google may sometimes associate searches with Colombia (set geographic target in Search Console).
Slightly more expensive than .com — $25-35/year.
Who .co fits
New startups and tech companies (angel.co as example). Brand alias — if you're brand.com, brand.co as add-on. E-commerce and business sites as a .com alternative.
Pricing and registration
$25-35/year (Namecheap, GoDaddy). Premium .co names $1,000-100,000+.
Via Sayt.uz 320,000 sum/year.
Sayt.uz practice
3% of Sayt.uz clients register .co — mostly startups and SaaS projects. Tip: if you're launching a startup and brand.com isn't available, .co is a good alternative. Otherwise grab it alongside the main .com — for brand protection.