A new token reward system is now live for watching the Overwatch League Stream with Twitch. Connect you're (platform you play Overwatch on)'s account to your twitch account and you'll receive 1 token per map viewed. Watching live is required for this to work. Archives seemingly don't count. For reference it costs 100 tokens for a single Owl skin in game. Though it may seem like a grind, it nicely rewards people who stick with the streams each week.
Here's an excerpt of the full verbiage found on this page.
"To earn one (1) League Token per map win, start by logging in to your Blizzard Battle.net account and linking it with your account on Twitch.tv, MLG.com, or overwatchleague.com.** Each time a map concludes during a live broadcast, eligible viewers will earn a League Token. Also, a percentage of lucky fans viewing the live broadcast when a match ends will be awarded 100 League Tokens, enough for a home-team skin of their choice!***"
Each matchup has the potential of at most 5 maps and at the least 4 depending on performance. In a single night you can recieve anywhere between 12 and 15 tokens and there are 4 stream nights a week. So we're talking 2 weeks for 1 skin. Additionally, there is a small chance some viewers can receive a full 100 tokens in a single map viewing. The percentage chance for this is based on the number of viewers watching. Here's more info on the whole system.
Here is the fine print on the chances of getting 100 tokens...
"The number of free home-team skins awarded per match determined as follows: 2*SQRT(N), where “N” equals the number of eligible participants (value $0). Odds of winning free skin depend on number of eligible entries received."
Unfortunately, it does seem like there are limitations on what countries can even participate with all this.
Some good news for everyone though.
Additionally, there is an unlock system on twitch for an exclusive set of Overwatch league themed skins. These skins will unlock for everyone once the twitch audience reach a group goal through a system based on cheering and bits. Basically viewers of the stream can buy bits to cheer on their favorite teams in chat. For every 100 bits acquired, they will unlock 1 of the 26 emotes released for the platform which can be used in chat. After a threshold is passed everyone will be able to redeem the exclusive skin of that week for in game. Right now, they have a tracer skin on the path for an unlock. The total amount of bits raised is close to 10,000,000 as of this post and 40,000,000 is needed for it to unlock. As far as I can tell, when this happens, everybody that has linked their overwatch platform accounts with twitch can redeem this "loot" as it's referred to. More info on this here. You can check the progress of bits raised by going on the live stream of the Overwatch League twitch account. It's below the stream.

If you want to know more on the whole Overwatch League skin system in general I made a forum post talking about it here. It's now a post for discussing Overwatch league overall, but the original post in question is near the bottom in a spoiler block.
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