The Business Platinum Card from American Express is offering 100,000 total bonus points through January 25, 2017 (which is just a couple weeks from now):

50,000 bonus points after spending $5,000 in the first three months
50,000 more bonus points after spending another $10,000 in the first three months

Credit card links have been removed from posts and added to the menu bar at the top of every page of MileValue under the heading Top Travel Credit Cards.

Check out Scott's full review here.
A Short History Lesson
In October of 2016, American Express added

Several cards not only give you points when you meet their sign up bonuses and spend on them, but also rebate points back to you when you redeem your rewards.

This post covers the Business Platinum Amex, the Citi / AAdvantage Platinum Select MasterCard, and the Barclaycard Arrival Plus, which are all offering temporarily elevated, lucrative sign up bonuses at the moment and offer rebates on redemptions.

Credit card links have been removed from posts and added to the menu bar at the top of every page of MileValue under the heading Top Travel Credit Cards.

Enhanced Business Platinum by

I am writing to you now from the beautiful state of Bahia, Brazil. If you've never traveled to this area I highly recommend it.

The coast is full of paradisiacal beaches, delectable seafood and spicy stews (the best of which in my opinion is moqueca), samba music, capoeira, and inland just a few hour drive from the Salvador airport is Chapada Diamantina, a national park and wonderland of plateaus, mountains, waterfalls, and limestone caves underneath it all where you can snorkel in the subterranean lakes and rivers.

Virgin Atlantic is dramatically altering its award charts for bookings made January 16, 2017 or later.

The United States goes from two regions to three.
The year round price is no more. Now we will have off peak and peak prices.
Economy and Premium Economy prices for most of the year drop dramatically.

There are data points rolling in from Reddit of people claiming the $450 annual fee on their American Express Business Platinum card is (unexpectedly) waived the first year.

This is not true of every single report, but many have noticed in their card agreements with American Express a line about the $450 annual fee being waived for the first year of card membership.

In case you missed the news: through January 25, 2017, the American Express Business Platinum Card is offering 100,000 total bonus Membership Rewards after spending $15,000 in the first three months.

Through December 31, 2016, you can earn double the rewards on purchases that normally fall into the non-bonused category of spend when you use your Amex card at eligible small businesses. The only stipulation is that you register your card first.

The Business Gold Rewards Card from American Express Open now comes with 50,000 bonus Membership Rewards after spending $5,000 on your card in the first three months the account is open.

Credit card links have been removed from posts and added to the menu bar at the top of every page of MileValue under the heading Top Travel Credit Cards.

The normal offer for the Business Gold Rewards Card is 25,000 points after spending $5,000. This improved offer is twice is good as it was before, and the best we've seen in years.

I get questions all the time like this:
Hi, I have a million American Express Membership Rewards/Chase Ultimate Rewards/Citi ThankYou Points, what is the best transfer partner to go from [here] to [there.]
There are basically two ways to answer the question:

Look at award charts of all the points' transfer partners and then look for award space using the cheapest miles. I used this method to suggest to my friend that he transfer his Membership Rewards to Flying Blue miles to get from Denver to Tel Aviv.

In 2014, American Express made it so you could get the bonus only once per lifetime on personal cards, and in February 2016 that rule was extended to business cards.

But there might be a targeted exception. Reader g passes along a targeted offer he got for the American Express Platinum Card.

The offer is to open the American Express Platinum Card with 50,000 bonus Membership Rewards after spending $5,000 in the first three months.

American Express is offering a 30% transfer bonus to Virgin Atlantic through May 31, 2016. For the next four weeks, 1,000 Membership Rewards will transfer to 1,300 Etihad Guest Miles.

This is huge news because there is also currently a 30% discount on Virgin Atlantic economy awards through May 11, 2016. Combining this transfer bonus with that sale means you can book awards from the Eastern United United States to London for 10,000 Membership Rewards plus $135 with great availability for the next 11 months if you act right now.