Google's search page has changed quite a bit over the years, even the way they handle search results has been tweaked and altered and improved over time as technology has gotten faster and smarter. Now Google appears to be testing new things within Search by changing the color of results links from blue to black in color. The black links aren't something that everyone is going to notice currently, of course, as this isn't a complete rollout for every user. Although there is nothing wrong with testing out fresh ideas and seeing if things improve the user experience, it appears that users who have been seeing the different colored links may not be happy with the change, as multiple people who have noticed them pop up have taken to Twitter to express their discontent over the tweak.
According to the details and image, the only thing that has changed, so far at least, is the main link itself which is appearing black instead of blue, while the text under the link as well as the web address haven't changed at all. There is no current explanation as to why Google have made this particular change which is rather minor, when you think about it, but Google puts plenty of thought into just about everything it does even if it's something as simple as choosing a color for a product. In fact, Google is reported to have made $200 million from a test it did in the past to help two designers decide on the shade of blue to use with advertising links.
Attention to detail is an important trait and it's one that Google tends to utilize with many things, so there is likely a reason behind the change of the link colors on its Search page. Whether or not it turns out to be as lucrative of a move as before when they were deciding on the shade of blue to use is unclear but that was likely a special case as Google made it a big to-do by publicly grabbing user input. According to the comments from users who have seen these show up, a product-wide rollout for everyone may not be in the cards in the near future.