1. What are the most current working links?
2. Is this card churnable?
3. How frequently can I apply for these cards?
4. Do I have to close my previous card before reapplying?
5. I got the 60K card and bonus but when I finished the spend on my second 60K card I did not get the bonus. What happened?

[1] What are the most current working links?

There is a standard offer for 50K points after $1K spend in 4 months. (No landing page is available for this offer; lnik taken from wiki for http://www.flyertalk.com/forum/citi-...amex-citi.html.)

There are no known 60K offers available. The most recent one expired in late September 2014.

[2] Is this card churnable?
In the past, this card has been easily churnable. However, in December 2014 Citi began inserting language into some applications and landing pages disqualifying current Hilton Visa cardholders & requiring an 18-month wait from the date of the previous card's cancellation. The application link listed above does not include this restriction, and FTers have confirmed that they have been approved through this application despite being current or recent holders of another Citi Hilton card.

[3] How frequently can I apply for these cards?
You can only apply for ONE Citi card in a week or TWO in two months (60 days). To be safe, it is frequently suggested to wait 8+ days between ANY two Citi applications and 65+ days until your third Citi application of ANY kind. These are rolling dates, so you have to wait at least 60 days (65+) from your second application to your 4th applications, and so forth.

If math is not your strong suit, you can use: http://www.timeanddate.com/date/duration.html.

Example:
Day 0 - Citi HHonors Card #1
Day 8 - Citi AA Personal Card
Day 65 - Citi AA Business Card
Day 73 - Citi HHonors Card #2
Day 130 - Citi TY Card

[4] Do I have to close my previous card before reapplying?
Not if you use the application link above. As stated above, in December 2014 Citi began introducing new application pages requiring an 18-month wait since cancellation of the prior card.

Note that when you close an account, Citi may not "free up" the credit limit from that card for as long as 6 months. So if you're going to apply within 6 months, it's better to not cancel beforehand.

[5] I got the 60K card and bonus but when I finished the spend on my second 60K card I did not get the bonus. What happened?
There appears to be a problem with Citi crediting you with both bonuses but Hilton not crediting the second bonus because their system sees it as a duplicate.

You need to open up a case, preferably with Hilton, and explain that you have two separate cards (feel free to explain one is for business and one for personal if they ask why you have multiple cards and you feel like explaining). You also need to diligently check back with them and make sure that they do not close the case as you already got the bonus.

This is very much a YMMV situation. Depending on who you talk to and where, this can be a relatively short process or a particularly unpleasant and long one. Best advice: Be nice to the CSRs and get them on your side or HUACA until you find someone useful.

For some people it may be worth getting the 50K card instead, possibly trying to "bump the bonus" to 60K and getting it as a 10K adjustment instead.