Is there any option to add mangas to Black list, so they won't e shown in "Releases"? because there are some mangas I will [b]read and wish to keep Releases list as short as possible.

You can view your reading list and it should show little red indicators when a new chapter has been released. You can also choose to sort your list that way in the options.

At this point, we don't have a way to exclude specific series from the releases list.

Well, for me most important to look for new mangas, and a lot of those, that I don't like is making choice way harder at the release list.

This. It would be really great if you had the possibility to "hide" a certain series so it won't show up in the releases page or in your research. It gets hard to find potentially interesting manga if the same series I don't want to read keep showing up.
Or maybe we could filter the categories in the releases page just as we do with the genres, that would be really helpful too.

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

While searching you can choose Only show manga not on any of my lists in advanced searching.

Yes, but you can't exclude just one of the lists. Which means that to exclude a manga you'll inevitably end up excluding others you're interested in (be it of the same genre or from another list).

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

I agree with train93, it would be very useful to be able to exclude only specific lists.

For example if you're looking for a series that you think is on one of your lists, but not the 'complete series' ones : currently you can't choose which lists to check, but with such a feature you could check only the 'wish ' and 'reading' lists.