Announced in October 2010 as part of the "Back to the Mac" event, Lion was the first big step towards Apple's goal of integrating developments made in iOS to the Mac OS.
Lion was also the first Mac OS to be released exclusively through the Mac App Store, this allowed for a much lower pricetag as no DVD had to be pressed or packaging made. Lion saw only five updates:
10.7.1 - August 2011
10.7.2 - October 2011 (added iCloud)
10.7.3 - February 2012
10.7.4 - May 2012
10.7.5 - September 2012
All with bug fixes, some with minor updates to Safari and language additions.