Merhaba! I have never really had a lesson on "hakkında." I have learned to use it only by watching what others write. But now I am discovering that it takes a possessive pronoun, just as "için" and "ile" and others do. Is this right? Can someone give me a quick explanation of "hakkında" or direct me to one that I have somehow missed. I am starting to think that "hakkında" is made up of suffixes, but I can´t find any explanation except the dictionary definition. For instance, what is "hakkımda"? Sorry to be so dense, but I know you are all used to it with me. Teşekkürler!

Here is a short explanation:

hakk-ın-da       -ın is possesive(2. and 3. person) suffix

hakk-ım-da       -ım is possesive (1. person) suffix

hakkında can be translated as "about him/her/it" or "about you"

hakkımda can be translated as "about me"

Hakkında with pronouns

Pronoun + possessive suffix  +  hak+ k + personal marking + da[de]

*Note that, the middle consonant "k" doubles when it takes vowel.

 Ben      + im         +   hakkımda

 Literally---->  In about of me ---> About me

 Sen    +  in          + hakkında ----> About you

 O  + n +  un         + hakkında ----> About him/her

 * Note that buffer "n" comes before possesive suffix.

Bizim  hakkımızda ---> About us

Sizin  hakkınızda  ---> About you [plural]

Onların  hakkında ---> About them

*Note that  with 3th plural person we don´t normally put "lar".

Hakkında with person names

Person name +  hakkında

Atatürk hakkında ---> About Atatürk

Sezin  hakkında  ---> About Sezin

Kenan hakkında ---> About Kenan

Hakkında with place/ things

Name of place/ thing  +  hakkında

Amerika  hakkında  ---> About America

İstanbul  hakkında  ---> About Istanbul

İstanbul hakkında bir kitap yazdı. ---> He/She  wrote a book about Istanbul.

Bu durum  hakkında ---> About this situation

This also works with plurals:

hakkımızda - About us <- You can find pages called "Hakkımızda" on many Turkish web sites.

hakkınızda - About you (plural): İnsanlar sizin hakkınızda ne düsünüyor? What people think about you?

I suppose that "about them" would be "hakklarında", but I haven´t noticed it very often... even Uncle Google gives just 5130 results for this word :| See Tunci´s post below: "Onların hakkında"

Yeah k is doubled there but I think it is because it is pronounced with double k in Arabic.. We dont write the word with double k when it is alone in Turkish but when we add a suffix after it we pronounce the second k. I guess there are some other examples too. This is an interesting gramatical event. It doesnt happen with every k.

Yes, it is an interesting grammatical event.

This doubbling  is seen in a limited number of words [Arabic words ] ending in the consonants "b, t, d, k , l , s, z , m and  n "

The final consonant is doubled when a vowel-initial suffix is attached onto it. Consonant doubling is not seen when a consonant-initial suffix is attached. 

Examples ;

his [feeling ] ---> hissi  [ his/her feeling ]

sır [ secret ] ----> sırrı [ his/her secret ]

hat[ line ]  ----> hattı [ his/her/its line ]

Rab [ God ] ----> Rabbi [his/her God]

haz [ pleasure ] ----> hazzı  [his/her pleasure ]

tıp  [ [medicine ] ----> tıbbi  [medical]

Çok teşekkür ederim! Together, you have given me a full lesson! This is all extremely interesting -- I guess I have just never run into "hakkında" in a construction like this before. ... One more question, though: What does "hak" mean all by itself? I have looked in the dictionary, but none of the definitions seems quite right. I imagine I am missing the point again. 

I always say, there is nothing better than "an interesting grammatical event,"  and this has certainly be one for me. Thank you again!

Hakk has 12 meanings in Ottoman dictionary:

http://www.osmanlicaturkce.com/?k=hakk&t=%40

I guess here the second meaning suits:

2. Dava ve iddia. cause and claim.

What do you think about his cause or claim?

I guess this sentence turned into this one:

What do you think about him?

But this is my theory

So "hakk" is an Arabic word that came by way of Ottoman Turkish, yes? And I have learned something else surprising here: You actually say each k! I knew that every letter was pronounced in Turkish, but somehow I didn´t realize that both k´s would be sounded. But now I have listened to the pronunciation on the dictionary here, and I can hear both k´s. It is as if you are saying hak-kın-da, yes? 

Turkish is full of surprises!

Çok teşekkür ederim, gokuyum.