I was thinking that on the one hand there may be an ענין to give to a non-Jewish organization that you've benefitted from (e.g. Wikipedia) as a way to train yourself in the middah of הכרת הטוב (hakarat hatov, gratefulness); on the other hand, maybe it's still better to only give to Jewish institutions.
Are there any halachic/hashkafic sources that deal with this question that you are aware of?
R Avrohom Chaim Feuer has an entire chapter in his book The tzedakah treasury (pp. 406ff) regarding donations to non-Jews. He writes
We provide financial support to the gentile poor (Gittin 61a, YD 151:12) [...] [R Pesach Feinhandler in] Responsa Avenei Yashpei (YD 1:193) maintains that one may deduct charitable donations to non-Jews from his maaser obligation. However he does suggest that the concept of darkei shalom, i.e., fostering harmonious, peaceful coexistence only applies when the non-Jew asks for Jewish aid. If the non-Jew does not request Jewish aid and does not expect it, there is no obligation to volunteer a contribution because there are sufficient non-Jews who can support those causes.
But note however the caveat from R Moshe Goldberger in his book Priorities in Tzedaka p. 82
One may give to secular or non-Jewish charities in order to promote peace darchei shalom. It would depend if the money goes for causes that are in accordance with the Torah. For example, if a [secular Jewish] community center is open on Shabbos, it is forbidden to support it with any type of funds.
My personal practice, for what it is worth, is to donate a moderate amount to non-Jewish charities which ask and which I benefitted from (and Wikipedia typically one of them) but to reserve the vast majority of my tzedaka for Jewish causes.
Of course, consult your rabbi before implementing anything you learn here
Are you talking about giving to institutions, causes, campaigns, etc., or only to the non-Jewish poor? I don't know about the former. About the latter, charity must be given to the non-Jewish poor ‘in the interests of peace’. [Gittin 59b, Shulchan Aruch Yoreh Deah 151:12]
Mishnah in Gittin 59b:
The following rules were laid down in the interests of peace... The poor of the heathen may not be prevented from gathering gleanings, forgotten sheaves, and the corner of the field, in the interests of peace.
The practice is not restricted to pe'ah. The Rambam writes:
Any "stranger" that is mentioned [in Scripture] with regards to the gifts for the poor can only refer to a convert, for it states regarding ma'asér sheni [the second tithe], (Deut. 14:29) Then the Levite...and the stranger...shall come. Just as a Levite is a member of the covenant, so also the stranger is a member of the covenant. Nevertheless, we do not prevent the poor of the Gentiles from these gifts. Rather, they may come along with the poor of Israel and take them for the sake of peaceful relations. [Mishneh Torah, Gifts to the Poor 1:9]
The facts: Only 6% of Jewish mega-gifts (>$10M) go to Jewish institutions. Most go to universities, health-related charities, and the arts and culture. [Tobin, Gary A., Jeffrey R. Solomon and Alexander C. Karp. Mega-Gifts in American Philanthropy: General & Jewish Giving Patterns Between 1995-2000, San Francisco: Institute for Jewish & Community Research, 2003].
