Quoting from the above blog post from MyHeritage.com's blog:
We’re excited to announce major updates and improvements to DNA Matching rolled out today for all our users. Anyone who took a MyHeritage DNA test, and anyone who uploaded DNA data from another service, will now receive more accurate DNA Matches; more plentiful matches (about 10x more); fewer false positives; more specific and more accurate relationship estimates; and indications on lower confidence DNA Matches to help focus research efforts. We also added the long-requested Chromosome Browser feature, described below.
These improvements have been many months in the making by our Science Team. They took much time and effort because we wanted to perfect the science and provide our users with optimal results.The blog post goes into detail and answers questions such as "What is DNA Matching?" and "How does DNA Matching work?" The post also explains how the matching technology was improved. The post is quite detailed. If you have taken a DNA test, particularly one from MyHeritage, I suggest you read this post.