Partiko by far, it has replaced IG and WhatsApp and helped me to delete fb from my phone (still use it on my mac for promos).
Partiko also helps to sign up friends on STEEM, I just tell them if you need to msg me directly use bit.ly/MyPartiko ;)
Also, you can still post to many other dApps like memestagram, palnet, weedcash.network, busy, steampeak etc, all just by adding the relevant hashtag for each.
Thanks