I use social media every single day. It helps me build awareness towards what I do and having a large audience for my interests is motivating me to generate content. But is it productive to post during the weekends? Isn't that content somehow wasted if you'll have less people reading it than if you would have posted it during working days?
If you post during the weekends, make sure you remember to share your article on Monday morning and on Wednesday as well. It works for me, so even if I've published an article on Sunday afternoon, like this one, sharing it afterwards helps me getting views all week long. Usually I have more views on Monday, than on Sunday.
Have in mind that when you publish online it's not like the printed press. But press are modernising as well. Even though most printed publications didn't use have weekend issues, it was because of the readers' reading habits and that has changed a little bit. Nowadays there are Sunday publications, which are consumed in a different way than the weekdays' issues. It is assumed that the readers have more time to spend on Sunday; it's a day they'll use to relax, or catch up with what they've missed.
Grabbing some attention is what we're all aiming for when publishing, so regularly adding content, discussing interesting topics and being there whenever the reader wants to consume your articles, are must haves in order to properly engage your audience.
The more dedicated you are to what you do, the more you want to speak about it. It comes naturally, you are authentic when doing it and your readers will notice it. If you generate valuable content and your readers see that, it doesn't matter when you're posting your stuff, as your readers follow you, they want to read what you're writing.
So is posting on weekends efficient? Test it! If you're only talking about it, if you're only planning to publish, it won't work until you actually do it. It's better to publish an article on a Sunday, instead of not publishing it at all.