What are some alternatives?
When comparing Pearltrees and wallabag, you can also consider the following products
Raindrop.io - All your articles, photos, video & content from web & apps in one place.
Pocket - When you find something you want to view later, put it in Pocket.
Tagpacker - A free tool to quickly collect, organize, and share your favorite links.
Diigo - Diigo is a powerful research tool and a knowledge-sharing community
Instapaper - Instapaper is a simple tool to save web pages for reading later.
Pinboard - Pinboard is a personal archive for things you find online and don't want to forget.